Stereotypic behavior in animals (also called "repetitive" or "compulsive" behavior) has been defined by some researchers as acts that are repetitive and constant, which may appear to serve no obvious purpose, and may even be injurious. One of the most common of these behaviors is, for example, crib-biting by horses--grabbing and biting of the feed bin or of parts of the structure in which the horse is housed (also called "cribbing"--see U.S. Pat. No. 4,692,451 for a description of this behavior, associated behaviors, and resulting problems). Another common behavior in dogs is compulsive licking of itself--even to the point of aggravating a sore ("lick granuloma" or "acral lick"). Stereotypies may show some degree of variation, and may be unlike the more typical behaviors such as cribbing and licking, in that they have no features of repetitive motion, but are characterized rather by motionless staring or a frozen body position.
The repetitive behaviors of animals and the compulsive behaviors of humans have both responded to treatment with some of the same drugs. See, e.g., regarding treatment of acral lick with drugs that have shown benefit in human obsessive-compulsive disorder (OCD), Rapoport, J. L., Clin. Neurophar. 15:Suppl. 1 Pt A:261A-262A, 1992; Rapoport, J. L. et al., Arch. Gen. Psychiatry 49:517-521, 1992. See also Smith, K. C. and Pittlekow, M. R., J. Am. Dermatol. 20:860-861, 1989, wherein it was reported that onychophagia and skin picking responded to treatment with (-) enantiomers of opioid antagonists, which have been effective also in compulsive hair pulling in cats, feather picking in birds, acral lick in dogs and cribbing in horses (Dodman, N. H., Vet. International 6:13-20, 1994; Dodman, N. H. et al., J. Am. Vet. Med. Assoc. 193:815-819, 1988; Turner, R., Proceedings of Annual Conference of the Association of Avian Veterinarians: Aug. 31-Sept. 4, 1993, Nashville, Tenn., pp. 116-118). See also U.S. Pat. No. 4,692,451, the contents of which are incorporated herein by reference in their entirety. Studies of this type provide justification for the conclusion that the same underlying physiological processes are involved in causation of the animal and human behaviors. Therefore, they should all respond positively to new methods of therapy.